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253 words

javax.persistence.FetchType - JPA enum

javax.persistence
Enum FetchType

java.lang.Object
    java.lang.Enum<javax.persistence.FetchType>
        javax.persistence.FetchType
Implemented Interfaces:
Serializable, Comparable<FetchType>
Defines strategies for fetching data from the database. The EAGER strategy is a requirement on the persistence provider runtime that data must be eagerly fetched. The LAZY strategy is a hint to the persistence provider runtime that data should be fetched lazily when it is first accessed. The implementation is permitted to eagerly fetch data for which the LAZY strategy hint has been specified.

Example:

   @Basic(fetch=LAZY)
   protected String getName() { return name; }
Since:
JPA 1.0
See Also:
Basic
ElementCollection
ManyToMany
OneToMany
ManyToOne
OneToOne
FetchType EAGER
Defines that data must be eagerly fetched.
Defines that data must be eagerly fetched.
Since:
JPA 1.0
FetchType LAZY
Defines that data can be lazily fetched.
Defines that data can be lazily fetched.
Since:
JPA 1.0
FetchType valueOf(String name)

Returns the enum constant of this type with the specified name.

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type.

Parameters:
name - the name of the enum constant to be returned.
Returns:
the enum constant with the specified name
Throws:
java.lang.IllegalArgumentException - if this enum type has no constant with the specified name
java.lang.NullPointerException - if the argument is null

FetchType[] values()

Returns an array containing the constants of this enum type.

Returns an array containing the constants of this enum type.

This method may be used to iterate over the constants as follows:

for (FetchType c : FetchType.values())
    System.out.println(c)
Returns:
an array containing the constants of this enum type, in the order they are declared

This documentation page is derived (with some adjustments) from the open source JPA 2 RI (EclipseLink)
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
Object Relational Mapping (ORM) JPA 2 providers include Hibernate, EclipseLink, TopLink, OpenJPA and DataNucleus.
Object DB is not an ORM JPA implementation but an Object Database for Java with built in JPA 2 support.